Remote Earth Potential Procedure
- Place reference electrode at a location remote (10 – 30m) from all cathodically protected structures. The remote reference electrode is not directly over any buried metallic structure or shielded by such structure;
- Be sure that reference electrode is in good contact with moist soil ;
- Connect reference electrode to the negative terminal of voltmeter using a long spool of suitable wire.
- Connect positive lead wire to voltmeter;
- Place voltmeter on 2 volt or less DC scale;
- Contact each buried metallic structure with the positive test lead without moving the reference electrode.
- Test and measure voltage for each structure under investigation. Acquire data for each structure as quick as possible to avoid nature potential fluctuation and /or interference.
Electrical Continuity Criteria
ΔV≤ 2 mV, the structures are electrically continuous.
ΔV≥ 10 mV, the structures are electrically isolated.
10> ΔV>2 mV, it is inconclusive and further diagnostic testing is required